Spark-plug.



PATENTED MAY 23, 1905.

G. L. HERZ.

SPARK PLUG.

APPLICATION FILED JULY 14.1904.

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6&9 Mama UNITED STATES Patented May 23, 1905.

GUSTAVF. L. HERZ, OF NElV YORK, N. Y.

SPARK-PLUG.

SPECIFICATION fOlming part of Letters Patent No. 790,571, dated May 23, 1905.

Application filed July 14:, 1904- Serial No. 216,514.

To (Z7. 2071,0721, it may concern:

Be it known that I, GUSTAVE L. Hnnz, a subject of the Emperor of Austria-Hungary, and a resident of the borough of Manhattan, in the city and State of New York, have invented new and useful Improvements in Spark-Plugs, of which the following is a specification.

My invention relates to improvements in spark-plugs, and has more particularly for its objects to provide certain improvements in the construction, form, and arrangement of the several parts whereby the use of gaskets between the inner insulator and the shell is obviated and in which the liability of the conducting-wire electrode to become carbonized is reduced to a minimum.

A further object is to provide a strong and durable plug in which the inner insulator is protected throughout its length within the outer shell.

A practical embodiment of my invention is represented in the accompanying drawings, in which Figure 1 represents the spark-plug in top plan. Fig. 2 is a side view of the same. Fig. 3 is a vertical central section through the plug. Fig. 4: is an inverted plan view of the plug. Fig. 5 is a detail view, in side elevation, of the inner insulator. Figs. 6, 7, and 8 are respectively top, side, and bottom plans of the outer insulator. Fig. 9 is a side view of the bolt which is fixed to the inner insulator before the walls of the head of the bolt have been crimped. Fig. is a cross-section in the plane of the line A A of Fig. 3, and Fig. 11 is a plan view of the washer interposed between the top of the outer insulator and the cap.

The shell of the plug comprises an inner member 1, an outer member 2 3, and an intermediate member et. The inner member 1 is provided with the usual exteriOrly-screwthreaded portion 5 for the attachment of the plug to the engine-cylinder. The intermediprises a cap 2 and a nut 3, having a screwthreaded engagement therewith. A terminal plate 6 is secured on the cap 2 by the nut 3, to which terminal plate the wire 7 is secured. This terminal plate 6 is permitted to freely rotate on the cap 2 to prevent binding or twisting of the wire 7. The bore of the shell is provided with a taper 8, which taper in the present instance is formed in the bore of the inner member 1.

The inner insulator is denoted by 9, and it is provided with a tapered portion 10, fitted to the taper 8 of the bore in the shell. The inner end of the insulator 9 is provided with stepped reduced portions 11 and 12, forming an increasing space between the periphery of the insulator and the inner wall of the shell. This space is utilized to prevent the collection of carbon on the conducting-wire electrode, as will hereinafter appear. The outer end of the insulator is provided with a reduced portion 13, having a circumferential groove 14, for the purpose of attaching a bolt permanently thereto. The head of the bolt which is to be permanently attached to the inner insulator is hollow and is herein denoted by 15. The screw-threaded shank of the bolt is denoted by 16. The head 15 fits over the reduced portion 13 of the inner insulator and is crimped into the groove 14.. The screwthreaded shank 16 of the inner insulator-bolt has a screw-threaded engagement with the cap 2 of the outer member, so that as the cap 2 is screwed inwardly the tapered portion of the inner insulator will engage the taper of the bore in-the shell, thus drawing the inner insulator snugly into position within the shell and at the same time hold the inner, intermediate, and outer members assembled.

The inner end of the insulator 9 is provided with a recess 17, forming an angular seat for the angular head 18 of the conducting-wire 19, which passes centrally through the said insulator. The outer end of this conducting wire 19 is screw-threaded, as shown at 20, and is engaged with the screw-threaded bore of the bolt carried by the insulator. This screwthreaded engagement between the conducting-wire 19 and the bolt carried by the insulator permits the conductor to be drawn into position within its recess 17 the angular engagement between the head and recess serving to prevent the conducting-wire from turning as it is being drawn to its place. The conducting-wire electrode comprises a cup 21, secured to the conducting-wire 19 by means of a screw-bolt 22, which screws into the head 18 of the said conducting-wire. When the parts are in position, the periphery of the cup-shaped electrode is brought substantially in alinement with the mouth of the bore in the shell. The cup 21 is preferably provided with a point 23, projecting therefrom, to centralize the spark. The shape of the electrode is such as to ofier the smallest possible sur' face to the direct flame within the cylinder. The small space formed at the mouth of the bore in the shell serves to keep the periphery of the electrode free from carbon as the gases are forced by the same.

A convenient means for holding the inner, intermediate, and outer members assembled is as follows: The intermediate member 4 is provided with recesses 24 in its top. A washer 25 is interposed between the top of the intermediate member and the cap2. The bottom of the cap is provided with teats 26, which interlock, together with the washer 25, with the intermediate member. The top of the inner member is provided with recesses 27, the bottom of the intermediate member with recesses 28, and pins 29 are engaged with correspondingrecesses 27 28.

A spark plug constructed as herein described is one in which the parts will not be liable to become deranged under the constant jar to which these plugs are subjected when in use. Furthermore, the plug is very strong and the inner insulator is thoroughly protected throughout its length. It will be seen that the conductingwire may expand and contract without affecting its insulator, because of the loose sliding fit of the angular head 18 of the wire within the recess 17 in the insulator. Furthermore, the use of gaskets is obviated, which gaskets dry out under the high temperatures to which the plug is subjected and rapidly become useless, as they permit the parts to become loosened, and thus facilitate the breaking of the insulators.

It is evident that changes might be made in the construction, form, and arrangement of the several parts without departing fromthe spirit and scope of my invention. Hence I do not wish to limit myself strictly to'the structure herein set forth; but

What I claim is 1. A spark-plug comprising a shell consisting of inner, intermediate and outer members, a conducting-wire, a conducting-wire insulator located within the shell and having a tapered-joint connection therewith and means other than the conducting-wire, carried by the insulator for securing said insulator to the outer member of the shell.

2. A spark-plug comprising a shell consisting of inner, intermediate and outer members and a conducting-wire insulator within the shell having a tapered-joint connection therewith, a conducting-Wire extending through the plug and a bolt carried by the insulator having a screw-threaded engagement with tllieguter member for holding the parts assemb e 3. A spark-plug comprising a shell consisting of inner, intermediate and outer members,

- means for interlocking the members, a conducting-wire, a conducting-wire insulator located within the shell and means carried by the insulator other than the conducting-wire for holding the parts assembled.

4. In a spark-plug, a cap, a terminal plate rotatably mounted on the cap and anut engaging the cap for holding the terminal plate against unintentional removal.

5. In a spark-plug, a shell forming one electrode, a conducting-wire,-an insulator therefor secured within the shell, an outwardlyflaring cup-shaped electrode carried by the conducting-wire within the shell with its periphery substantially in alinement with the mouth of the shell, and a point projecting from the periphery of the cup-shaped electrode for concentrating the spark at the mouth of the shell.

6. In aspark-plug, a shell forming one electrode, a conducting-wire, an insulator therefor secured within the shell, an outwardlyflaring cup-shaped electrode located within the shell with its periphery substantially in' alinement with the mouth of the shell and a bolt separate from the conducting-wire connecting the cup-shaped electrode to the conducting-wire.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 13th day of July, 1904:.

GUSTAVE L. HERZ.

Witnesses:

FREDK. HAYNES, F. GEORGE BARRY. 

